Wind power is considered one of the cleanest, most environmentally friendly energy sources presently available, and wind turbines have gained increased attention in this regard. A modern wind turbine typically includes a tower, generator, gearbox, nacelle, and one or more rotor blades. The rotor blades capture kinetic energy of wind using known foil principles. The rotor blades transmit the kinetic energy in the form of rotational energy so as to turn a shaft coupling the rotor blades to a gearbox, or if a gearbox is not used, directly to the generator. The generator then converts the mechanical energy to electrical energy that may be deployed to a utility grid.
The size, shape, and weight of rotor blades are factors that contribute to energy efficiencies of wind turbines. Presently, large commercial wind turbines in existence and in development are capable of generating from about 1.5 to about 12.5 megawatts of power. These larger wind turbines may have rotor blade assemblies larger than 90 meters in diameter. Accordingly, efforts to increase rotor blade size, decrease rotor blade weight, and increase rotor blade strength, while also improving rotor blade aerodynamics, aid in the continuing growth of wind turbine technology and the adoption of wind energy as an alternative energy source.
Presently known rotor blades, while increasing in size and thus advantageously generating higher lift forces, may have disadvantages. For example, higher lift forces result in correspondingly heavy loads on the rotor blades and other wind turbine components. These loads must be managed to prevent the rotor blades from failing or becoming damaged. Known systems and methods for managing the loads include, for example, controller modifications to and active flow control of the rotor blades. However, these systems and methods generally may not be able to respond quickly enough to the changing dynamic flow state on a rotor blade to adequately manage the heavy loads. Another known solution includes the use of aerodynamic tailoring of the rotor blade. However, the rotor blade must be aerodynamically tailored to a particular wind speed. Thus, the adjustment of an aerodynamically tailored rotor blade to the changing dynamic flow state may be relatively limited to the particular wind speed, and may not perform optimally at other wind speeds.
Accordingly, there is a need for a rotor blade assembly that can quickly adjust to a changing dynamic flow state, and that can adjust to a wide variety of wind speeds. Additionally, a rotor blade assembly that allows for smaller, lighter rotor blades that generate higher lift forces would be advantageous. Further, a rotor blade assembly that allows retrofitting of various components to existing rotor blades to provide adjustable features and higher lift forces would be desired.